Yes independent sleep = does all the work himself
. Sounds like he's doing great!
My guess is that he probably needs a bit of a longer day or a bit less day sleep. Do you have a sense of whether he does better with shorter naps/longer night, or is better to keep the long naps and have a slightly shorter night?
Given your first A time is pretty short for his age, and second one is also relatively short, I would probably work on extending those by 10 mins or so every 3-4 days so overall his day gets a bit longer and he has some longer awake periods. Many LOs easily handle 3.5h A time across the day at this age, and it might be at the moment he just isn't tired enough to sleep soundly at night. They do sound like UT night wakings to me.
What do you think?